Hot water heating system

ABSTRACT

A hot water heating system is provided with: a hot water heating device; a heating terminal; a heat circulation circuit; a circulation means; and an expansion-absorbing means. The hot water heating device is provided with: a heating passage; a heating means for heating a heat medium inside the heating passage; a pressure detection means; a supply passage connected to the heating passage; an opening/closing means for the supply passage; and a control means which opens the opening/closing means to supply the heat medium when the internal pressure of the heating passage is less than a reference value. The control means determines that the positional relationship between the circulation means and the expansion-absorbing means is inappropriate when the pressure detected by the pressure detection means at the moment the circulation means starts to be driven is lower than the pressure detected prior to driving the circulation means.

BACKGROUND Technical Field

The disclosure relates to a hot water heating system which performsheating using heat of a heat medium heated by a hot water heatingdevice.

Description of Related Art

Conventionally, a hot water heating system has been widely used toperform heating by supplying hot water heated by a hot water heatingdevice as a heat medium to a heating terminal. For example, as in PatentDocument 1, such a hot water heating system is configured so that,during a heating operation, the heat medium heated by a heating part ofthe hot water heating device is supplied to the heating terminal, andthe heat medium returning from the heating terminal is heated again bythe heating part. The hot water heating device is connected to theheating terminal via a heat circulation circuit, and includes a pumpwhich circulates the heat medium to the heat circulation circuit and anexpansion tank for absorbing a volumetric expansion of the heat mediumdue to an increase in temperature. In addition, the hot water heatingdevice has a hot water supply function which supplies a hot water supplyheated by the heating part.

Moreover, in the case where there are a plurality of heating terminalsor in the case where the distance between the hot water heating deviceand the heating terminal is large, the passage length of the heatcirculation circuit increases. In such a case, since the load on thepump of the hot water heating device increases, an external pump capableof circulating the heat medium in conjunction with the pump of the hotwater heating device is provided outside the hot water heating device.

In addition, as the passage length of the heat circulation circuitincreases, the amount of the heat medium to be circulated increases, sothat the amount of the volumetric expansion of the heat medium alsoincreases. Therefore, in the case where the capacity of the expansiontank of the hot water heating device is insufficient, the expansion tankmay be provided outside the hot water heating device. Further, on theassumption that the expansion tank is provided outside, it is alsopossible that the hot water heating device does not include an expansiontank in the first place.

RELATED ART Patent Document(s)

Patent Document 1: Japanese Laid-open No. 2015-222137

SUMMARY Problems to be Solved

In the case where the hot water heating system is configured byproviding the expansion tank and the external pump outside the hot waterheating device, the expansion tank and the external pump are arranged inthe heat circulation circuit which connects the hot water heating deviceand the heating terminal. In that case, if the positional relationshipbetween the expansion tank and the external pump is inappropriate, aninternal pressure of the flow passage of the heat medium in the hotwater heating device at the time driving of the external pump startswill be lower than that before the driving. As a result, the hot waterheating device determines that the heat medium decreases, andautomatically supplies the heat medium or issues a notification whichprompts the supply.

However, since the cause of the decrease in the internal pressure is notthe decrease in the heat medium, the decrease in the internal pressureis not eliminated even if the heat medium is supplied. For this reason,there is a risk that the hot water heating device would make anerroneous determination of a leak of the heat medium and thus notifyoccurrence of the leak and stop the heating operation.

An objective of the disclosure is to provide a hot water heating systemcapable of determining that a positional relationship between acirculation means and an expansion-absorbing means is inappropriate.

Means for Solving the Problems

In the disclosure of claim 1, a hot water heating system includes a hotwater heating device, a heating terminal, a heat circulation circuitconnecting the hot water heating device and the heating terminal, acirculation means provided in the heat circulation circuit, and anexpansion-absorbing means provided in the heat circulation circuit toabsorb a volumetric expansion of a heat medium due to an increase intemperature. The hot water heating device includes a heating passageconnected to the heat circulation circuit, a heating means which heatsthe heat medium in the heating passage, a pressure detection means whichdetects an internal pressure of the heating passage, a supply passageconnected to the heating passage, an opening/closing means for openingand closing the supply passage, and a control means which opens theopening/closing means to supply the heat medium when the pressuredetection means detects that the internal pressure of the heatingpassage is less than a preset reference value. The control meansdetermines that a positional relationship between the circulation meansand the expansion-absorbing means is inappropriate in a case where adetection pressure of the pressure detection means at the time drivingof the circulation means starts is lower than a detection pressurebefore the driving of the circulation means.

According to the above configuration, during a heating operation, thehot water heating system circulates the heat medium heated by the hotwater heating device to the heat circulation circuit through thecirculation means. The expansion-absorbing means provided in the heatcirculation circuit absorbs the volumetric expansion of the heat mediumdue to the increase in temperature to prevent damage or leak resultingfrom an increase in the internal pressure of the heat circulationcircuit and the heating passage. The internal pressure of the heatingpassage is detected by the pressure detection means of the hot waterheating device, and when the amount of the heat medium decreases and theinternal pressure of the heating passage becomes less than the referencevalue, the control means supplies the heat medium. In the case where theinternal pressure of the heating passage at the time the driving of thecirculation means starts is lower than the internal pressure before thedriving, the control means determines that the positional relationshipbetween the circulation means and the expansion-absorbing means isinappropriate. Therefore, in a test operation performed at the time ofconstruction of the hot water heating system, since it is possible todetermine that the circulation means and the expansion-absorbing meanshave been connected in an inappropriate positional relationship at thetime the driving of the circulation means starts, they can bereconnected in an appropriate positional relationship.

In the disclosure of claim 2 according to claim 1, the hot water heatingdevice includes a bypass passage which branches off from the heatingpassage downstream of the heating means and connects to the heatingpassage upstream of the heating means so as to bypass the heatcirculation circuit. The bypass passage includes a heat exchanger forperforming heat exchange between the heat medium and a hot water supply.

According to the above configuration, the hot water supply can be heatedusing the heat medium, so that it is possible to configure a hot waterheating system having a hot water supply function.

The disclosure of claim 3 according to claim 2 further includes adistribution valve capable of adjusting a distribution ratio of the heatmedium at a branching part of the heating passage and the bypasspassage.

According to the above configuration, since the heated heat medium canbe distributed for heating and for hot water supply, it is possible toconfigure a hot water heating system which can simultaneously performheating and hot water supply.

Effects

According to the hot water heating system of the disclosure, it ispossible to determine that a positional relationship between thecirculation means and the expansion-absorbing means is inappropriate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing an overall configuration of a hot water heatingsystem according to an embodiment.

FIG. 2 is a view showing a configuration of a hot water heating deviceaccording to the embodiment.

FIG. 3 is a view showing a hot water supply system in which acirculation pump and an expansion tank are arranged in an inappropriatepositional relationship.

DESCRIPTION OF THE EMBODIMENTS

Hereinafter, the configuration for implementing the disclosure will bedescribed based on the embodiments.

Embodiments

First, the overall configuration of a hot water heating system 1 will bedescribed based on FIG. 1. The hot water heating system 1 is configuredto perform a heating operation in which heating is performed bysupplying a heat medium heated by a hot water heating device 2 to aheating terminal 3. The hot water heating system 1 includes a hot waterheating device 2, a heating terminal 3, a heat circulation circuit 4connecting the hot water heating device 2 and the heating terminal 3, anexternal pump 5 (circulation means) provided in the heat circulationcircuit 4, and a closed expansion tank 6 (expansion-absorbing means)provided in the heat circulation circuit 4 to absorb a volumetricexpansion of the heat medium due to an increase in temperature, and thepassage through which the heat medium flows is configured as a closedtype. For example, the heating terminal 3 may be a hot air heatingdevice which blows air heated by the heat of the heat medium, a panelheater or a floor heating device which performs heating by using theradiant heat of the heat medium and natural convection of air, and thelike, and a plurality of these devices may also be connected.

The heat circulation circuit 4 includes a terminal circulation circuitpart 4 a which circulates and supplies the heat medium to the heatingterminal 3 through driving of the external pump 5, and a heatingcirculation circuit part 4 b which supplies the heat medium from theterminal circulation circuit part 4 a to the hot water heating device 2and supplies the heat medium heated by the hot water heating device 2 tothe terminal circulation circuit part 4 a. To have an appropriatepositional relationship with respect to the external pump 5, theexpansion tank 6 is provided upstream of the external pump 5 of theterminal circulation circuit part 4 a. The heating circulation circuitpart 4 b is connected to the upstream of the expansion tank 6 of theterminal circulation circuit part 4 a. During the heating operation,even if the supply of the heat medium from the hot water heating device2 is temporarily interrupted for a hot water supply operation asdescribed below, heating can be continued with the heat medium whichcirculates through the terminal circulation circuit part 4 a.

Next, the hot water heating device 2 will be described based on FIG. 2.During the heating operation, the hot water heating device 2 heats theheat medium and supplies the heat medium to the heat circulation circuit4. In addition, it has a hot water supply function which supplies hotwater by adjusting the tap water heated using the heat of the heatmedium to a hot water supply setting temperature. The hot water heatingdevice 2 is configured so that the hot water supply function can be usedeven during the heating operation.

The hot water heating device 2 includes a heating passage 10 connectedto the heat circulation circuit 4, a heating part 11 (heating means)which heats the heat medium in the heating passage 10, a built-in pump13 provided in the heating passage 10, a pressure sensor 14 (pressuredetection means) which detects an internal pressure of the heatingpassage 10, a supply passage 15 connected to the heating passage 10, anopening/closing valve 16 (opening/closing means) for opening and closingthe supply passage 15, and a control part 17 (control means) whichcontrols the heating operation and the like. During the heatingoperation, the built-in pump 13 can circulate the heat medium inconjunction with the external pump 5. The heating part 11 heats the heatmedium by using, for example, the heat of combustion when a fuel gasindicated by an arrow F and air indicated by an arrow AS are mixed andburned.

The hot water heating device 2 includes a first bypass passage 18(bypass passage), a hot water supply heat exchanger 19 (heat exchanger)provided in the first bypass passage 18, a water supply passage 20, ahot water passage 21, etc. To bypass the heat circulation circuit 4, thefirst bypass passage 18 is branched off from the heating passage 10downstream of the heating part 11, and joins the heating passage 10upstream of the built-in pump 13. The water supply passage 20 suppliestap water indicated by an arrow CW to the hot water supply heatexchanger 19. The hot water supply passage 21 supplies a hot watersupply heated by the hot water supply heat exchanger 19 to a hot watertap or the like, as indicated by an arrow HW.

Next, the heating passage 10 will be described. The heating passage 10includes a first temperature sensor 22 between the heating part 11 andthe built-in pump 13, and includes a second temperature sensor 23downstream of the heating part 11. The first temperature sensor 22detects the temperature of the heat medium flowing to the heating part11. The second temperature sensor 23 detects the temperature of the heatmedium heated by the heating part 11. Based on the detectiontemperatures of these sensors, the heating part 11, the built-in pump13, etc. are controlled by the control part 17 so that the temperatureof the heated heat medium can become a predetermined temperature.

A first distribution valve 24 (distribution valve) is provided at abranching part of the heating passage 10 and the first bypass passage18. The first distribution valve 24 can adjust a distribution ratio tobe adaptable to the heating operation, the hot water supply operation,and the simultaneous operation of heating and hot water supply, anddistributes the heat medium heated by the heating part 11 to the heatingpassage 10 and the first bypass passage 18. The distribution ratio ofthe first distribution valve 24 is adjusted so that the heat medium issupplied only to the heating passage 10 during the heating operation andis adjusted so that the heat medium is supplied only to the first bypasspassage 18 during the hot water supply operation. In addition, duringthe simultaneous operation of heating and hot water supply, with thedistribution ratio of the first distribution valve 24 adjusted so thathot water supply is prioritized, the heat medium is distributed to theheating passage 10 and the first bypass passage 18. The heat mediumdistributed by the first distribution valve 24 to the heating passage 10is supplied to the heat circulation circuit 4 as indicated by an arrowHS.

A pressure release valve 25 capable of releasing the pressure in theheating passage 10 is provided between the heating part 11 and the firstdistribution valve 24. A heat return temperature sensor 26 which detectsthe temperature of the heat medium returning from the heat circulationcircuit 4, as indicated by an arrow HR, is provided upstream of thebuilt-in pump 13. A supply passage 15 for supplying the heat medium, asindicated by an arrow AF, is connected between the built-in pump 13 andthe heat return temperature sensor 26. The supply passage 15 is providedwith an opening/closing valve 16, and a pressure sensor 14 is providedin the supply passage 15 downstream of the opening/closing valve 16.

Next, the water supply passage 20 and the hot water supply passage 21will be described. The water supply passage 20 includes a seconddistribution valve 27, a flow adjustment valve 28, a flow sensor 29, andan incoming water temperature sensor 30. A second bypass passage 31 isbranched off from the water supply passage 20, and the seconddistribution valve 27, which is provided at the branching part and canadjust the distribution ratio, distributes tap water to the water supplypassage 20 and the second bypass passage 31. The flow adjustment valve28 adjusts the flow rate of the tap water entering the seconddistribution valve 27. The flow sensor 29 detects the flow rate of thetap water entering the second distribution valve 27. The incoming watertemperature sensor 30 detects the temperature of the tap water enteringthe second distribution valve 27.

The second bypass passage 31 joins the hot water supply passage 21 at ajunction part C. A hot water delivery temperature sensor 32 is providedbetween the junction part C of the hot water supply passage 21 and thehot water supply heat exchanger 19. The hot water delivery temperaturesensor 32 detects the temperature of the hot water delivered from thehot water supply heat exchanger 19.

A hot water supply temperature sensor 33 is provided at the downstreamend of the hot water supply passage 21. The hot water supply temperaturesensor 33 detects a hot water supply temperature of the hot water supplywhich is mixed from the hot water heated by the hot water supply heatexchanger 19 and the tap water flowing through the second bypass passage31. During the hot water supply operation, the distribution ratio of thesecond distribution valve 27 is adjusted so that the hot water supplytemperature can become a set temperature.

Next, the control part 17 will be described based on FIG. 1 and FIG. 2.Based on detection signals of sensors provided in the hot water heatingdevice 2, the control part 17 controls the heating part 11, the built-inpump 13, the external pump 5, the first distribution valve 24, etc. tocontrol each of the heating operation, the hot water supply operation,and the simultaneous operation of heating and hot water supply. For thecontrol of the heating operation, the control part 17 is communicablyconnected to the heating terminal 3 and the external pump 5,respectively. The control part 17 is connected to an operation terminal34 for performing a setting operation and the like on the hot waterheating device 2. The operation terminal 34 includes, for example, adisplay part 35 capable of displaying information such as temperature,and a switch part 36 for performing a setting operation and the like.

When the pressure sensor 14 detects that the internal pressure of theheating passage 10 is less than a preset reference value, the controlpart 17 opens the opening/closing valve 16 to supply the heat medium. Inthe case where any abnormality is detected in the hot water heatingdevice 2, the abnormality is notified through the operation terminal 34,and an operation stop or the like is performed for safety. The referencevalue of the internal pressure of the heating passage 10 is preset basedon an internal pressure or the like obtained, for example, through anexperiment in which the heat medium is heated and circulated, and it maybe adjusted through the operation of the operation terminal 34.

At the time of construction of the hot water heating system 1, afterconnecting each device, the installer introduces the heat medium intothe hot water heating system 1, performs a test operation of the heatingoperation and the like, and checks whether there is any abnormality suchas a leak of the heat medium. In the test operation, if a detectionpressure of the pressure sensor 14 at the time driving of the externalpump 5 starts is lower than the detection pressure before driving, thecontroller 17 determines that the positional relationship between theexternal pump 5 and the expansion tank 6 is inappropriate. Then, thedetermination of the inappropriateness is, for example, displayed on thedisplay part 35 of the operation terminal 34 to notify the installer.

The determination of the positional relationship between the externalpump 5 and the expansion tank 6 will be described. When driving of theexternal pump 5 starts, the heat medium is pushed out to downstream ofthe external pump 5, and the heat medium upstream of the external pump 5equivalent to the pushed amount is drawn into the external pump 5.

As shown in FIG. 1, if the expansion tank 6 is provided upstream of theexternal pump 5 (which is an appropriate position with respect to theexternal pump 5), the heat medium equivalent to the amount pushed outfrom the external pump 5 is pushed out from the heating terminal 3, apart thereof flows into the hot water heating device 2, and theremaining part flows through the terminal circulation circuit part 4 a.As heated heat medium equivalent to the amount of the heat medium whichhas flowed into the hot water heating device 2 is supplied from the hotwater heating device 2 to the terminal circulation circuit part 4 a, theamount pushed out from the external pump 5 is in line with the amountdrawn into the external pump 5. Therefore, the internal pressure of theheating passage 10 detected by the pressure sensor 14 of the hot waterheating device 2 does not change before and after the driving of theexternal pump 5 starts.

On the other hand, as shown in FIG. 3, if the expansion tank 6 isprovided downstream of the external pump 5 (which is an inappropriateposition with respect to the external pump 5), a part of the heat mediumpushed out from the external pump 5 flows into the expansion tank 6, theheat medium flowing into the hot water heating device 2 decreases, andthe heat medium pushed out from the hot water heating device 2decreases. Then, a part thereof flows into the hot water heating device2 and the remaining part flows through the terminal circulation circuitpart 4 a. Heated heat medium more than the amount of the heat mediumflowing into the hot water heating device 2 is drawn into the externalpump 5 from the hot water heating device 2 so that the amount pushed outfrom the external pump 5 is in line with the amount drawn into theexternal pump 5. For this reason, the internal pressure of the heatingpassage 10 detected by the pressure sensor 14 of the hot water heatingdevice 2 is lower than that before the driving of the external pump 5starts. Therefore, the inappropriateness of the positional relationshipbetween the external pump 5 and the expansion tank 6 can be determinedbased on the detection pressure of the pressure sensor 14 when theexternal pump 5 is driven. In the case where the amount of the heatmedium is insufficient, the detection pressure of the pressure sensor 14becomes less than the reference value regardless of whether the externalpump 5 is driven, and thus distinction can be easily made.

The operation and effect of the disclosure will be described. At thetime of construction of the hot water heating system 1, after connectingeach device, the installer introduces the heat medium into the hot waterheating system 1 and performs a test operation of the heating operationand the like. When driving of the external pump 5 starts, in the casewhere the internal pressure of the heating passage 10 is lower than thatbefore the driving of the external pump 5, since it is possible todetermine that the positional relationship between the external pump 5and the expansion tank 6 is inappropriate, the installer can immediatelyreconnect them in an appropriate positional relationship. Therefore, itis possible to prevent the use of the hot water heating system 1 inwhich the external pump 5 and the expansion tank 6 are connected in aninappropriate positional relationship, and prevent a situation in whichthe heating operation is stopped due to the erroneous determination of aheat medium leak.

Moreover, the hot water heating device 2 includes the hot water supplyheat exchanger 19 for performing heat exchange between the heat mediumand the hot water supply at the first bypass passage 18 branched offfrom the heating passage 10, and the hot water supply can be heatedusing the heat medium. Therefore, it is possible to configure a hotwater heating system 1 having a hot water supply function. In addition,since the first distribution valve 24 which can adjust the distributionratio of the heat medium is provided at the branching part of theheating passage 10 and the first bypass passage 18, it is possible toconfigure a hot water heating system 1 which can simultaneously performheating and hot water supply by distributing the heated heat medium forheating and for hot water supply.

A person skilled in the art can implement various modifications to theabove-described embodiments without departing from the spirit of thedisclosure, and the disclosure includes such modifications.

DESCRIPTION OF REFERENCE NUMERALS

-   -   1: Hot water heating system    -   2: Hot water heating device    -   3: Heating terminal    -   4: Heat circulation circuit    -   5: External pump (circulation means)    -   6: Expansion tank (expansion-absorbing means)    -   10: Heating passage    -   11: Heating part (heating means)    -   14: Pressure sensor (pressure detection means)    -   15: Supply passage    -   16: Opening/closing valve (opening/closing means)    -   17: Control part (control means)    -   18: First bypass passage (bypass passage)    -   19: Hot water supply heat exchanger (heat exchanger)    -   20: Water supply passage    -   21: Hot water supply passage    -   24: First distribution valve (distribution valve)    -   34: Operation terminal

What is claimed is:
 1. A hot water heating system, comprising a hot water heating device, a heating terminal, a heat circulation circuit connecting the hot water heating device and the heating terminal, a circulation means provided in the heat circulation circuit, and an expansion-absorbing means provided in the heat circulation circuit to absorb a volumetric expansion of a heat medium due to an increase in temperature, wherein the hot water heating device comprises a heating passage connected to the heat circulation circuit, a heating means which heats the heat medium in the heating passage, a pressure detection means which detects an internal pressure of the heating passage, a supply passage connected to the heating passage, an opening/closing means for opening and closing the supply passage, and a control means which opens the opening/closing means to supply the heat medium when the pressure detection means detects that the internal pressure of the heating passage is less than a preset reference value, and the control means determines that a positional relationship between the circulation means and the expansion-absorbing means is inappropriate in a case where a detection pressure of the pressure detection means at the time driving of the circulation means starts is lower than a detection pressure before the driving of the circulation means.
 2. The hot water heating system according to claim 1, wherein the hot water heating device comprises a bypass passage which branches off from the heating passage downstream of the heating means and connects to the heating passage upstream of the heating means so as to bypass the heat circulation circuit, and the bypass passage comprises a heat exchanger for performing heat exchange between the heat medium and a hot water supply.
 3. The hot water heating system according to claim 2, further comprising a distribution valve capable of adjusting a distribution ratio of the heat medium at a branching part of the heating passage and the bypass passage. 